It's almost like the connection between computer scientists and programmers. The first group develops tools, the other uses in their development of a product.

Biological knowledge is more prominent in the Bioinformatician's background, while, computer knowledge and high programming skills are among the core requirements for a Computational biologist. However, they both need to be capable of making a bridge between these two fields.

However, I think the speed of the growth and development of these fields are quite high that sometimes titles cannot provide a proper explanation. Perhaps different names will be introduced in the future that can give a better fit for the complexity and beauty of this area.